Spark plug



May 15, 1923.

S. P. MILLER SPARK PLUG 8 i y ,j @15%,

. m il Filed July 14 Patented May 15, 1923.

SAMUEL P. MILLER, OF CHICAGO, ILLINOIS.

SPARK PLUG.

aplicaron 1aed Juiy 14, 191s. serial No. 310,613.

T o ZZ whom' it may concern:

Be it known that I` SAMUEL I. MILLER, a citizen ot' the United States. and a resident of the city ot' Chicago, county of Cook, and

State of Illinois, have invented certain new and useful Improvements in Spark Plugs, ot' which the following is a specification.

My invention relates to new and useful improvements in spark plugs and has for its object the provision o't a device of this character in which the corrosion of the electrodes will be reduced to a miniiuum.

()ther' object-s will appear hereinafter.

The invention consists in the combinations and arrangements ot parts hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings forming a part ot' this specification, and in which,

Fig. 1 is a perspective view of a spark plug embodying my invention.

Fig. 2 is a central vertical sectional view of a spark plug embodying my invention.

Fig. 3 is a front elevational view of my invention.

Fig. 4 is a trout elevational view of a modified form of my invention.

The approved form of construction, as illustrated in the drawings, is adapted to be used with the usual and ordinary form of spark plug, comprising a thimble 5 the lower portion ot' which is threaded, as at 6, tor reception by the threaded opening in the engine cylinder. rlhe usual jam nut 7 is employed tor threading into the interior ot' the thimble The usual insulating core 8 is employed having the usual nut 9 and terminal post 10. My invention relates solely to the electrodes and the stems forming the same. The usual stem 11 is used as part of the electrodes, the stem being threaded at its upper end for the reception of the nut 9 and the terminal post 10. Provided adjacent the lower end of the stem 11 is a suitable shoulder 12, preferably made integral with the stem 11, this shoulder 12 being adapted to engage against the shoulder which is usually provided at the upper end of the slot which is provided in the insulatin core 8, as will be readily understood. n that portion of the stem 11 which projects downwardly beyond the shoulder 12, I have provided a series of grooves 13 and 13, these grooves being shown here as limited to two, although the number may be increased. Surrounding the lower portion ol the stem 11 is a sleeve 14, the upper end ot which is crimped to vseat in the groove 13. This sleeve 14 is also'crimped to seat in the second groove 13', as clearly shown in Fig. 3, this crimping vforming a shoulder 15 which extends around the interior of the sleeve. The lower end of the sleeve member l-.l extends beyond the end of thestem 11 and is also crimped inwardly to form a socket 16 for the purpose of loosely retaining a spherical terminal 17 in the space which intervenes between the lower end of the member 11 and the lower end of the member 14. As clearly shown, the lower en d 18 ofthe member 11 is tapered to form a suitable flowing point. Extending around the sleeve member 14 and formed therethrough are suitable openings 19, said openings 19 leadin into the interior of the sleeve member 14. rojecting downwardly from the thimble 5 is a suitable bracket 20 having an opening positioned centrally in the lower portion thereof. Threaded into this circular opening is the cooperating electrode stem 11. This stem 11 has provided at its under surface a suitable slot 2l, whereby the stem may be adjusted relatively to the cooperating stem 11. The stem 11 is also provided with a suitable sleeve 14. Similar grooves 13 and 13 are provided inthe stem 11 serving the same pur ose as grooves 13 and 13 in the stem 11. similar spherical terminal 17 is secured in the sleeve 14 in a similar manner to the one secured in the sleeve 14. Similar openings 19 project through the sleeve 14. In the modified form shown in Fig. 4, in the member 11 I have dispensed with the groove 13 and have provided the interior of the member 14 with threads adapted to cooperate with threads on the member 11', the member 11 being threaded throughout its length and crimped at one end to seat in. oove 13. Similarly, on the member 11 I ave provided a single groove 13, the interior of the member 14 being threaded to cooperate with the threads provided at the lower end of the member 11. The spherical members 17 and 17 are retained in the sleeve members 14 and 14 in a similar manner as already described. Upon the member 14 being threaded upon the member 11, theupper end thereof is crimped so as to seat snugly in the groove 13, thereby locking the sleeve 14 upon the member 11. k

ln Fig. 2 I have shown a modified form wherein only one slot 13 is provided, the sleeve 14 not being threaded. d

By forming the electrodes of the spark plugs as indicated, I have provided a spark plug in which the electrodes have rotating or revolving terminals. This results in a different portion of the terminal being utilized, while the device is in operation and results in keeping the terminals vthereof free from corrosion, and distributes wear. upon the terminals over the entire surface, there# by eliminating the possibility of pitting. Futhermore, the lower electrode is so constructed as to be adjustable, this feature adding' greatly to the eiciency of the device.

While I havel illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit ofthe invention. I, therefore, donot wish to be limited to' the precise details of construction set trodes; 'a sleeve secured to one end of each of said electrodes, there being a space formed between the free end of each sleeve of adjusting said electrodes relatively to cach other, substantially as described.

3. In a spark plug, a pair of' electrodes, cach comprising a stem; a shoulder mounted on one of said stems; a sleeve mounted on the adjacent ends of each of said stems; and vspherical members loosely mounted on the adjacent ends of said stems, substantially as described. l v

4. In a spark plug, a pair of electrodes having similarly shaped, alined securing members, and spherical terminals loosely mounted in, and protruding. from the adjacent ends of said securing members, one of said electrodes being adjustable relatively tothe other, substantially as described. y

5. A spark plug comprising -op-positely disposed electrodes having circumferential -grooves about their adjacent end portions; sleeves crimped about said electrodes to enage saidgrooves; and spherical terminals liiosely mounted in said sleeves, the ends of the sleeves being crimped to retain the ter- Aminals therein, substantially as described. 6. In a spark plug, a pair of electrodes, comprising a pair of stems; a socket mounted on the adjacent ends `of each of .saidv stems, and each adapted to retain a spherical terminal loosely mounted therein, substantially as described. j

vIn testimony whereof I have signed my name to this specification in the presence 4of two subscribing witnesses.

' j v f SAMUEL P. MILLER.

Witnesses:

j Josse.. R. H. rms,

B. G. RICHARDS. 4 

